/Engine/Plugins/Developer/Concert/ConcertMain/Source/ConcertTransport/Public/IConcertEndpoint.h
Callback when a message has been acknowledged by this remote endpoint
[FOnConcertMessageAcknowledgementReceived](API\Plugins\ConcertTransport\FOnConcertMessageAcknowledgement-) & OnConcertMessageAcknowledgementReceived()